this.Most end game raid bosses have extremely high defences, and high physical damage resists, so full STR does not give you as much DPS output compared to hybrid builds.Yep dex is better early but once you start raiding then str build is much better. When you use dex you are getting defense which is pretty useless. But early on before bossing having defense is good.Some rangers like using the more DEX based skills, not to mention sharpshot which every ranger uses, so DEX is a good option early on till you arrive at full time raiding where it's better to go hybrid.
DEX also gives you attack which you can never have too much of, and STR scales off as well.
Prot is the only end game raid where full STR reaps you dividends because of the insanely low physical resists and lower defences.
At end game a dex ranger will beat a str ranger 9/10 times. Dex may boost defence which is useless but it also boosts attack not to mention EVERY stat based skill. (Dbl shot isnt directly affected by str or dex, only indirectly boosted by str). Physical damage (str boosts this) is also the most heavily resisted damage at end game in most cases.
Str rangers were the meta pre tower when ranger skills were broken and totally useless. A lot of rangers still think full str is the best build without having actually tested or experienced the effects of dex. Now that the dex skills were buffed and with bosses having such high defence the need for dex has drastically increased.